This invention generally relates to a vascular catheter which delivers therapeutic fluid to a desired location within a patient's vasculature.
Therapeutic fluids such as those containing urokinase, streptokinase, tissue plasminogen activator (TPA) have been found effective in many instances in the treatment of vascular thrombosis. The systemic administration of such therapeutic agents is not always desirable because the entire body of the patient must be medicated in order to treat small vascular sites. Delivery of therapeutic fluids through vascular catheters directly to a desired treatment site is usually more effective and, moreover, with direct delivery higher concentrations of the therapeutic agent may be used in the treating solution.
In the direct delivery of therapeutic fluid to a thrombotic region in the patient's vasculature, it is highly desirable to limit the application of the therapeutic fluid only to the treatment site to limit the amount of therapeutic agent used (which can be very expensive) and to avoid over medicating the patient. Frequently, there are multiple treatment sites of various lengths which require the use of multiple catheters having at the distal end thereof drug delivery sections of various lengths to effectively deliver the treatment fluid only to the treatment site. In these instances, either a separate catheter must be used at each treatment site, which increases the time and the inconvenience of the procedure, or inefficient application of the treatment fluid must be accepted.
What has been needed is a catheter delivery system which can deliver therapeutic fluids to one or more thrombotic sites with means to adjust the effective length of drug delivery section of the catheter body, particularly after the catheter has been inserted into the patient's blood vessels. The present invention provides a catheter which satisfies this need.